In cellular wireless networks such as UMTS Terrestrial Radio Access Network (UTRAN) and an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), cells capable of covering different size areas are deployed to improve cell coverage or to offload traffic. In a UTRAN or E-UTRAN network, small cells capable of covering small areas (e.g., pico cells, relay cells, or femto cells) are deployed with overlay large cells capable of covering larger areas (also known as macro-cells). A network including large cells and small cells is referred to as a heterogeneous wireless communication network or, for simplicity, as a heterogeneous network.
Macro-cells and small cells may operate in the same carrier frequency or different carrier frequencies. Operating the macro-cells and small cells on the same frequency generates cell splitting gain, and as a result, increases system capacity. On the other hand, operating the macro-cells and small cells on different carrier frequencies helps to reduce the interference among cells. A user equipment (UE) such as a mobile phone or other device in communication with a network and moving in an area with a large number of small cells may experience frequent handovers due to the smaller coverage area of a small cell.